Recently, there have been proposed various technologies relating to a vehicle which can be driven in a manual driving mode in which a driver oneself drives the vehicle or in an autonomous driving mode in which a portion of or all of driving operations are autonomously performed, or technologies relating to a fully automated self-driving vehicle, based on a surrounding situation of the vehicle or a travel state (for example, the speed of the vehicle or control information such as steering, acceleration, braking, turn signal indicator, or actuator) of the vehicle, and these technologies have been put into practical use.
For example, PTL 1 discloses a travel control device configured to, when performing, on a host vehicle, autonomous steering control or autonomous acceleration/deceleration control, allow a driver to visually recognize the operating state of the autonomous steering control or the autonomous acceleration/deceleration control.